Reconciling the light-cone and nonrelativistic QCD approaches to calculating e{sup +}e{sup -}{yields}J/{psi}+{eta}{sub c}
- High Energy Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
It has been suggested in Ref. [A. E. Bondar and V. L. Chernyak, Phys. Lett. B 612, 215 (2005)] that the disagreement between theoretical calculations and experimental observations for the rate for the process e{sup +}e{sup -}{yields}J/{psi}+{eta}{sub c} at the B factories might be resolved by using the light-cone method to take into account the relative momentum of the heavy-quark and antiquark in the quarkonia. The light-cone result for the production cross section in Ref. [A. E. Bondar and V. L. Chernyak, Phys. Lett. B 612, 215 (2005)] is almost an order-of-magnitude larger than existing NRQCD factorization results. We investigate this apparent theoretical discrepancy. We compute light-cone distribution functions by making use of quarkonium wave functions from the Cornell potential model. Our light-cone distribution functions are similar in shape to those of Ref. [A. E. Bondar and V. L. Chernyak, Phys. Lett. B 612, 215 (2005)] and yield a similar cross section. However, when we subtract parts of the light-cone distribution functions that correspond to corrections of relative-order {alpha}{sub s} in the NRQCD approach, we find that the cross section decreases by about a factor of three. When we set certain renormalization factors Z{sub i} in the light-cone calculation equal to unity, we find a further reduction in the cross section of about a factor of two. The resulting light-cone cross section is similar in magnitude to the NRQCD factorization cross sections and shows only a modest enhancement over the light-cone cross section in which the relative momentum of the heavy-quark and antiquark is neglected.
- OSTI ID:
- 20868108
- Journal Information:
- Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 11 Vol. 74; ISSN PRVDAQ; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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